The present invention relates, in general, to integrated circuits and, more particularly, to monolithic radio frequency integrated circuits.
Radio frequency integrated circuits are widely used in communication applications. More particularly in portable wireless communication applications, the demand for small, reliable, power efficient, and cost efficient radio frequency integrated circuits is constantly increasing.
Bipolar complementary metal oxide semiconductor (BiCMOS) technology is conventionally used to fabricate the radio frequency (RF) integrated circuit dice that process small analog and mixed-mode signals. The BiCMOS technology includes the fabrication of both bipolar transistors and metal oxide semiconductor (MOS) field effect transistors. Therefore, the BiCMOS technology includes complicated manufacturing processes and is cost inefficient. Further, it is very difficult to include high efficiency integrated power amplifiers in a BiCMOS process. Thus, an off-chip power amplifier is used to process large signals.
The power amplifier can be fabricated using technologies such as an RF laterally diffused metal oxide semiconductor (LDMOS) technology. However, the RF LDMOS technology does not provide a level of integration that is sufficiently high for integrating RF analog and digital functions on a single die, and its applications are primarily limited to power amplification.
In addition, the circuits fabricated using BiCMOS and/or LDMOS technologies are generally high power circuits that are not suitable for applications where low power consumption is considered to be an advantageous feature. Such applications include battery powered portable wireless communication applications, e.g., pagers, cellular phones, modems in portable computers, etc.
Accordingly, it would be advantageous to have a semiconductor integrated circuit die and a process for fabricating the die. It is desirable for the die and the process to provide a high level of integration and a power efficient circuit. It is also desirable for the die to be able to perform both radio frequency analog circuit and digital circuit functions. It would be of further advantage for the process to be simple and cost efficient.